The document discusses the design of an energy efficient carry save adder using asynchronous adiabatic logic. It first discusses existing work on using double pass transistor logic with asynchronous adiabatic logic to design an energy efficient full adder cell. It then proposes using a carry save adder which can add 3 n-bit numbers using only 2 numbers of additions, reducing delay and improving performance. The document discusses the design of a static energy recovery full adder cell and use of double pass transistor logic to avoid signal degradation. It also provides background on asynchronous adiabatic logic which aims to reduce power dissipation by reusing stored energy.